Huawei Mate 9 wioth official beta version Android 8.0.0 Oreo and with EMUI 8.0.0 works really perfect. But if you want to make downgrade back to Android Nougat, you will find many tutorial on internet. But most of them doesnt work. In this article i will show tutorial, which work for 100 percent for Europe version of Huawei Mate 9 (C432 customization).
Before you make this downgrade, make backup of all your data, because they will be erased. At the end of this process, you will have Huawei Mate 9 with latest official firmware B198 and with locked bootloader.
How to downgrade Huawei Mate 9 from Android 8.0.0 Oreo to Android Nougat
1. unlock bootloader of your smartphone
2. download HWOTA8 for Huawei Mate 9
3. unzip downloaded file and flash twrp-oreo.img with command fastboot flash recovery_ramdisk twrp-oreo.img
4. copy rest of HWOTA8 (without twrp-oreo.img) to microSD card of your smartphone
5. power off your smartphone, start TWRP and install HWOTA8_update.zip from HWOTA8 folder on your microSD card
6. wait until installation finish, than wipe cache and make factory reset
7. enjoy Huawei Mate 9 with Androi 7.0 Nougat and EMUI 5.0.1